Pronounced Genetic Structure Associated With Differences in a Reproductive Trait and Climatic Barriers in Canadian Populations of the Western Toad (Anaxyrus boreas)

Aim: Identifying genetic groups within species' ranges is critical for inventorying diversity and delineating conservation units. For many North American amphibians, limited knowledge of genetic structure in Canada constrains effective conservation decision-making. The western toad (Anaxyrus boreas) has an extensive distribution in western North America and, with a large part of its range in Canada, represents an opportunity to fill gaps in our understanding of genetic structure in this part of the country. Curiously, toads to the east of the Canadian Rocky Mountains (CRMs) have a vocal sac and produce a distinct advertisement call, whereas toads to the west of the CRMs and in southern parts of the species' range lack these traits. We aimed to evaluate genetic structure across the Canadian range of western toads to determine whether these ‘Calling’ and ‘Non-calling’ populations are genetically distinct.